Java Deep Copy and Shallow Copy

Sep 16, 202361

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This text discusses the difference between shallow copy and deep copy in the context of a class. It explains that shallow copy does not create a new copy of the object, while deep copy does. It also mentions that when dealing with immutable objects like String and Integer, a new object needs to be created in memory to store new values.

Assuming we have a class.

We use two images below to illustrate the difference between shallow copy and deep copy.

Shallow Copy

Untitled Form

Deep Copy

Notes:#

Assuming we have a class and we perform a shallow copy.

At this point, the output result is

In other words, the shallow copy is not performed as shown in the previous illustration because the values in object x and object y are not the same. This is because String and Integer, as well as other wrapper classes, are immutable objects. When modifying the value of an immutable object, a new object needs to be created in memory to store the new value, and then the original reference is pointed to the new address.